in a forwarder, domains for which an NXDOMAIN response is expected should be added to the Exceptions for VPN Users section of the OpenDNS Dashboard. Most of the issues above were resolved when OpenDNS discontinued their advertising service, and started responding with NXDOMAIN and SERVFAIL instead of redirecting non-existing domains. See also DNSCrypt EDNS Client Subnet PhishTank Public recursive name server Response policy zone References External links Dark Reading: OpenDNS Goes Mobile Nov. 15, 2012 PC World: OpenDNS introduces VPN, content filtering for mobile devices Nov. 13, 2012 PC Magazine: OpenDNS Extends Company Security to Mobile Devices Nov. 13, 2012 Cisco software Companies based in San Francisco Alternative Internet DNS services Internet properties established in 2006 Content-control software Cisco Systems acquisitions 2015 mergers and acquisitions Software companies established in 2006